The Exposure and Analytical Core functions as a resource for all investigators within this Program Project and acts as a conduit of services between the Biomedical and Ecological components. This Core provides services in three main areas: 1.) animal handling and exposure, this includes mammals, invertebrates and aquatic organisms; 2.) chemical analysis and sample preparation, including assays of toxicants in tissue, blood sediment, and water; 3.) animal cell and tissue preparation, including isolation of homogeneous cell populations, surgery and necropsy. This Core furnishes a unifying focus for biomarker development by providing cell and tissue preparations from animals exposed under identical conditions to the Biomedical components. This allows for direct comparisons of the effectiveness of the biomarker assays under development. In addition, this Core conducts investigatory projects designed to provide information concerning the bioavailability of toxicants to the Biomedical components. These investigatory projects are performed in collaboration with members of the Ecology components who provide expertise regarding routes of exposure, relevant dosages and pharmacokinetic analysis. Thus the Core uses data provided by the Ecology components to furnish bioavailability information to the Biomedical components. In this way the Core integrates the findings of the Ecology components into the studies conducted by the Biomedical components. In the past, the Core conducted a pharmacokinetic analysis of the clearance of chromium from various organs after chronic exposure to chromate. In the coming grant period, the Core will conduct two investigatory studies, one concerns the bioavailability of ingested cadmium bound to protein in food while the other concerns the bioavailability of chromium after pulmonary exposure to chromate- contaminated soil. Both of these studies will be conducted with investigators of the Ecology components, and the cell and tissue samples from exposed animals will be delivered to investigators in the Biomedical components. Thus, these activities of the Core will serve to integrate the expertise of the Ecology and Biomedical components and provide services to both.